System and method of locating lightning strikes

Abstract

A system and method of determining locations of lightning strikes has been described. The system includes multiple receivers located around an area of interest, such as a space center or airport. Each receiver monitors both sound and electric fields. The detection of an electric field pulse and a sound wave are used to calculate an area around each receiver in which the lighting is detected. A processor is coupled to the receivers to accurately determine the location of the lighting strike. The processor can manipulate the receiver data to compensate for environmental variables such as wind, temperature, and humidity. Further, each receiver processor can discriminate between distant and local lightning strikes.

What is claimed is:  
     
       1. A system to determine a location of lighting strikes comprising: 
       a processor; and  
       a plurality of receivers coupled to the processor, wherein each of the plurality of receivers comprises an electric field sensor, an acoustic sensor, and a controller to provide a receiver output indicating a calculated time differential between an electric field pulse and a sound wave, the processor determines the location of lighting strikes in response to the output from the plurality of receivers.  
     
     
       2. The system of  claim 1  wherein each of the plurality of receivers are located up to at least one kilometer apart. 
     
     
       3. The system of  claim 1  wherein the processor compensates for wind speed and wind direction while determining the location of lighting strikes. 
     
     
       4. The system of  claim 3 , wherein the processor compensates for wind speed and wind direction in the absence of wind speed and wind direction measurements. 
     
     
       5. The system of  claim 1  wherein the processor compensates for temperature while determining the location of lighting strikes. 
     
     
       6. The system of  claim 1  wherein the processor compensates for humidity while determining the location of lighting strikes. 
     
     
       7. The system of  claim 1  wherein the plurality of receivers comprise three receivers. 
     
     
       8. A system to determine a location of lighting strikes comprising: 
       at least three receivers wherein each receiver comprises an electric field sensor, an acoustic sensor, and a controller to provide a receiver output indicating a calculated time differential between an electric field pulse and a sound wave; and  
       a processor coupled to the receivers to determine the location of lighting strikes in response to the output from the receivers.  
     
     
       9. The system of  claim 8  wherein the processor compensates for environmental conditions including wind speed and wind direction, temperature and humidity while determining the location of lighting strikes. 
     
     
       10. The system of  claim 9 , wherein wind speed is corrected for by 
       using angles between the receivers and the lighting location to compute estimated ranges R, using the following formula:  
       
         
             R=TOA*V=TOA *( c−V   w  cos (θ−Θ))  
         
       
       where TOA=measured time interval between the electromagnetic and sonic signals 
       V=effective sonic velocity  
       c=actual sonic velocity based on temperature  
       V w =wind speed  
       θ=azimuth direction measured from receiver to source  
       Θ=azimuth of wind vector.  
     
     
       11. The system of  claim 8  wherein each of the receivers are located up to one kilometer apart. 
     
     
       12. A method for determining a location of lightning strikes comprising: 
       locating a network of at least three electric field sensors and at least three sonic sensors in an area of interest;  
       collecting lightning strike information, including a time of arrival of an electric field pulse and an associated sound wave from a lightning strike;  
       processing the lightning strike information recorded by the at least three electric field sensors and the at least three sonic sensors, including measuring a time difference between the arrival of the electric field pulse and the sound wave at each electric field and sonic sensor; and  
       determining the location of the lightning strike.  
     
     
       13. The method of  claim 12  wherein determining the location of the lightning strike comprises compensating for environmental conditions including wind speed and wind direction, temperature and humidity. 
     
     
       14. The method of  claim 12  wherein the at least three electric field sensors are located up to one kilometer apart, and the least three sonic sensors are located up to one kilometer apart. 
     
     
       15. The method of  claim 12  wherein determining the location of the lightning strike comprises comparing the arrival of the electric field pulse and the sound wave for each pair of receivers. 
     
     
       16. The method of  claim 12  wherein the network comprises at least four electric field sensors and at least four associated sonic sensors. 
     
     
       17. The method of  claim 16 , wherein wind speed is corrected for by 
       using angles between the receivers and the lighting location to compute estimated ranges R, using the following formula:  
       
         
             R=TOA*V=TOA *( c−V   w  cos (θ−Θ))  
         
       
       where TOA=measured time interval between the electromagnetic and sonic signals 
       V=effective sonic velocity  
       c=actual sonic velocity based on temperature  
       V w =wind speed  
       θ=azimuth direction measured from receiver to source  
       Θ=azimuth of wind vector.  
     
     
       18. The method of  claim 12  wherein the processor compensates for wind speed and wind direction while determining the location of lighting strikes. 
     
     
       19. The method of  claim 12 , wherein the processor compensates for wind speed and wind direction in the absence of wind speed and wind direction measurements. 
     
     
       20. The method of  claim 12  wherein processing the lightning strike information comprises discriminating between lightning strikes based upon distance to filter out lightning strikes outside the area of interest.